Vitreo-retinal procedures are commonly performed to treat many serious conditions of the posterior segment of the eye. For example, vitreo-retinal procedures may treat conditions such as age-related macular degeneration (AMD), diabetic retinopathy and diabetic vitreous hemorrhage, macular hole, retinal detachment, epiretinal membrane, cytomegalovirus (CMV) retinitis, and many other ophthalmic conditions.
A surgeon performs vitreo-retinal procedures with a microscope and special lenses designed to provide a clear image of the posterior segment. Several tiny incisions just a millimeter or so in diameter are made on the sclera at the pars plana. The surgeon inserts microsurgical instruments through the incisions, such as a fiber optic light source to illuminate inside the eye, an infusion line to maintain the eye's shape during surgery, and instruments to cut and remove the vitreous body. A separate incision may be provided for each microsurgical instrument when using multiple instruments simultaneously.
During such surgical procedures, proper illumination of the inside of the eye is important. Typically, an optical fiber is inserted into one of the incisions in the eye to provide the illumination. A light source, such as a halogen tungsten lamp or high pressure arc lamp (metal-halides, Xe), may be used to produce the light carried by the optical fiber into the eye. The light passes through several optical elements (typically lenses, mirrors, and attenuators) and is transmitted to the optical fiber that carries the light into the eye.
The incisions are typically only made large enough to accommodate the size of the microsurgical instrument being inserted into the interior of the eye. Efforts to minimize the incision size generally involve reducing the size of the microsurgical instrument. However, a reduction in size can result in a reduction in strength or rigidity. Depending on the size of the microsurgical instrument employed, the incision may be small enough to render a resulting wound substantially self-healing, thereby eliminating the need to employ additional procedures to close the incision, such as sutures. Also, reducing the number of incisions may be accomplished by integrating various microsurgical instruments. For example, the optical fiber may be incorporated into the working end of a microsurgical instrument. This may eliminate the need for a separate illumination incision, and offers the advantage of directing the light beam, together with the microsurgical instrument, onto the target site through a common opening in the sclera. Unfortunately, at least some prior attempts at integrating illuminating optical fibers with microsurgical instruments have resulted in a decrease in illuminating efficiency or in other visualization problems that otherwise adversely effected the distribution of light emitted from the optical fibers.